The present invention relates to industrial circuit breakers and particularly to an assembly for reliably reseating the plunger of a flux-shifter type trip solenoid from its extended position in tripping engagement with a circuit breaker trip latch assembly.
The subject reset assembly has particular, but not necessarily limited application to a store energy, reclosure type circuit breaker, such as that disclosed in commonly assigned, copending application Ser. No. 52,276, filed June 25, 1979 now Pat. No. 4,251,702. The disclosure of this copending application is specifically incorporated herein by reference. As therein disclosed, a circuit breaker is equipped with a separate charging mechanism which is charged and then discharged to charge a spring-powered operating mechanism capable, when charged, to articulate breaker movable contacts from an open position to a closed position and, when discharged or tripped, from their closed to their open position. The charging mechanism also has the capability of being sustained in its charged condition to await subsequent discharge of the operating mechanism, whereupon it automatically discharges to abruptly recharge the operating mechanism. In many cases, the discharge of the operating mechanism is triggered by electrical activation of a flux shifting type trip solenoid in response to an overcurrent condition sensed by a solid state trip unit. Such solenoid activation creates an electromagnetizing flux in opposition to the holding flux of a permanent magnet normally effective in holding the solenoid plunger in its seated position against the bias of a spring. The spring then becomes overpowering, and the plunger is propelled to its extended position where it trippingly engages a trip latch assembly acting to trip or discharge the operating mechanism and thus open the breaker contacts. Since recharging of the operating mechanism by the charging mehcanism can occur very quickly, it is necessary that the solenoid plunger be reset, i.e., reseated, even more quickly in order that the trip latch assembly can reset itself soon enough to hold the charge imparted thereto by the charging mechanism. Otherwise the operating mechanism immediately discharges or 37 crashes" without ever closing the breaker contacts, a situtation detrimental to the operating mechanism.
It is accordingly an object of the present invention to provide an improved flux shifter reset assembly.
A further object is to provide an exceptionally fast acting flux shifter reset assembly of the above character.
Another object is to provide a flux shifter reset assembly of the above character acting in response to the opening movement of the breaker contacts to reseat the plunger of a flux shifter trip solenoid from its trip initiating extended position.
An additional object is to provide a flux shifter reset sytem which is equipped with means to trip the circuit breaker in response to the breaker contacts being blown open by high level fault currents.
Other objects of the invention will in part be obvious and in part appear hereinafter.